There is a general demand for effective and affordable renewable energy sources in many areas of computation and sensing. Interest in pervasive power has led to technological developments such as piezoelectric nanofibers, photovoltaic wires, and variable-capacitance generators, among other emerging technologies that are particularly well-suited to harvesting power from ambient energy sources. Pervasive power harvesting has applications in a broad variety of fields including medicine, defense, and consumer electronics. Power harvesting is particularly relevant to the rapidly growing field of electronic textiles (e-textiles), which has evolved from research curiosity into modular construction kits, but still operates using conventional power sources, rather than employing such novel energy sources.